The rotor for a mixer-refiner-reactor such as shown in U.S. Pat. No. 3,806,050 has raised bars for working through relatively viscous material under control of a stator that also has raised bars. The rotor bars are oriented to move a layer of material circumferentially through the stator, to move through the material as the layer moves, and to force the material axially back and forth as the bars pass through. The net orientation of the rotor bars relative to axial movement of material is preferably approximately neutral, with a slight tendency to favor one axial direction being tolerable.
The rotor bars tend to wear somewhat and are preferably formed of a relatively hard material. For example, U.S. Pat. No. 3,806,050 suggested casting groups of rotor bars on blocks of hard material and mounting rows of blocks on the rotor body. Since rotor bars have to be replaced occasionally, the total cost of rotor bar replacement is an important factor in the acquisition and operation of the machine.
The invention involves recognition of the problems and expense of rotor bar fabrication and replacement, and seeks a rotor construction that is simpler, cheaper, more efficient, and allows easy bar replacement. The invention also seeks versatility and a simple way of varying rotor bar configurations.